A new DC-free multimode code design with error correction capability for optical storage systems

DC-free run-length limited codes have been the cornerstone of all three generations of optical recording, CD, DVD and BD. Research into efficient coding methods is paramount for the upcoming fourth generation. A Multimode coding technique is an efficient coding method that has been reported in the literatures. Under multimode coding rules, a user word is translated into a plurality of possible candidate words, and among the candidate words the encoder selects the codeword with the least low-frequency spectral content. In our paper, we will present a new coding technique for constructing error correcting high-rate DC-free multimode code using a low-density parity-check (LDPC) code for future high-density optical recording. The scheme achieves reliable DC-suppression and obtains considerable bit error rate (BER) performance gain through the iterative decoding (or turbo equalization) with the concatenated detector.